The present invention relates to a refrigerator of a type having a refrigerator compartment, including a vegetable storage chamber, and a freezer compartment defined below the refrigerator compartment.
It is well known that the refrigerator has a plurality of utility compartments, respective inside temperatures of which are controlled to a different temperature appropriate for storage of particular food materials. The refrigerator very popular in the art has a freezer compartment defined at top of the refrigerator housing and a refrigerator compartment defined in the refrigerator housing at a location below the freezer compartment, and is generally referred to as a top-freezer refrigerator. The refrigerator compartment is usually divided into a refrigerating chamber and a crisper or vegetable storage chamber generally defined below the refrigerating chamber.
However, in view of ease of use, a bottom-freezer refrigerator has recently come into the mainstream. In the bottom-freezer refrigerator, the refrigerator compartment is positioned below the refrigerator compartment with the crisper located at the bottom of the refrigerator compartment. An example of this bottom-freezer refrigerator is disclosed in, for example, the Japanese Laid-open Patent Publication No. 5-71850.
Some prior art bottom-freezer refrigerators will now be discussed with reference to the accompanying drawings and particularly to FIGS. 9 to 11. Referring first to FIG. 9, the known bottom-freezer refrigerator comprises a generally rectangular box-like refrigerator housing 1, the interior of which is divided into a freezer compartment 2 and a refrigerator compartment 3 defined above the freezer compartment 2 and separated therefrom by means of an adiabatic partition wall 4. The freezer compartment 2 has an engine chamber 5 defined therein at a location rearwards of the refrigerator compartment 2 with respect to and opposite to a front door assembly (not shown), for accommodating therein a cooler 6 and a circulating fan 7 for creating a forced draft of cooling air. The refrigerator compartment 3 has a crisper or vegetable storage chamber 9 defined or positioned therein at the bottom thereof, and a low-temperature storage chamber 10 such as, for example, a chilled chamber or a partial freezing chamber defined or positioned therein at a location above the crisper 9. Reference numeral 8 represents a first cooled air return passage defined inside the engine chamber 5.
Reference numeral 11 represents an automatic temperature controller disposed at a lower rear deep area of the refrigerator compartment 3, in which controller 11 there are disposed a first cooled air supply regulator 12 for controlling the supply of a cooled air into the refrigerator compartment 3, a second cooled air supply regulator 13 for regulating the supply of the cooled air into the low-temperature storage chamber 10, a first cooled air discharge passage 14 for discharging the cooled air from the refrigerator compartment 3, a second cooled air discharge passage 15 for discharging the cooled air from the low-temperature storage chamber 10, and a second cooled air return passage 16 communicated with the first cooled air return passage 8. Reference numeral 17 represents a return port defined in a rear wall of the low-temperature storage chamber 10 and communicated with the second cooled air return passage 16 within the automatic temperature controller 11. Reference numeral 18 represents a discharge port communicated with the low-temperature storage chamber 10 and fluid-connected with the second cooled air discharge passage 15. Reference numeral 19 represents a return port defined in a rear wall of the refrigerator compartment 3 and communicated with the second cooled air return passage 16 within the automatic temperature controller 11. Reference numeral 20 represents a discharge duct having a cooled air discharge port 21 communicated with the refrigerator compartment 3, and communicated with the first cooled air discharge passage 14.
The flow of the cooled air in the prior art refrigerator shown in FIG. 9 will be discussed. Air cooled by the cooler 6 is forcibly supplied by the circulating fan 7 in part to the refrigerator compartment 3 through the first cooled air discharge passage 14, the first cooled air supply regulator 12 and the discharge duct 20 and in part to the low-temperature storage chamber 10 through the second cooled air discharge passage 15, the second cooled air supply regulator 13 and the discharge port 18. The cooled air supplied into the refrigerator compartment 3 flows through the return port 19 and the cooled air supplied into the low-temperature storage chamber 10 flows through the return port 17. The cooled air from the return port 19 and the cooled air from the return port 17 are subsequently returned to the cooler 6 through the second cooled air return passage 16 and the first cooled air return passage 8, respectively. In this way, the cooled air circulated within the refrigerator through the various compartments and chambers to cool those compartments and chambers to respective predetermined temperatures.
FIGS. 10 and 11 illustrate another prior art bottom-freezer refrigerator. The known bottom-freezer refrigerator best shown in FIG. 10 comprises a generally rectangular box-like refrigerator housing 22, the interior of which is divided into a refrigerator compartment 24 and a freezer compartment 25 defined below the refrigerator compartment 24 and separated therefrom by means of an adiabatic partition wall 23. The refrigerator compartment 24 which is most frequently utilized in home has a removable crisper box 26 mounted inside the refrigerator compartment 24 and slidably resting on the adiabatic partition wall 23. The refrigerator compartment 24 accommodates therein a first cooler 27, a first circulating fan 28 and a first temperature detecting means 29 for detecting the inside temperature of the refrigerator compartment 24. On the other hand, the freezer compartment 25 accommodates therein a second cooler 30, a second circulating fan 31 and a second temperature detecting means 32 for detecting the inside temperature of the refrigerator compartment 24.
As shown in FIG. 11, the refrigerating system employed in the refrigerator shown in FIG. 10 includes a compressor 33, a condenser 34, a decompressor 35, the first cooler 27 and the second cooler 30, all of which are fluid-connected in the order specified above.
Cooling of the refrigerator of the structure shown in FIGS. 10 and 11 is generally carried out by driving the compressor 33 in response to a signal from the temperature detecting means 32 disposed in the freezer compartment 25. Simultaneously with the drive of the compressor 33, the first and second circulating fans 28 and 31 are also driven to forcibly circulate the cooled air within the refrigerator compartment 24, including the crisper box 26, and the freezer compartment 25 to cool and freeze the food materials accommodated therein, respectively. When the freezer compartment 25 is cooled to a predetermined temperature as a result of the cooling operation, the compressor 33 is brought to a halt in response to a signal from the temperature detecting means 32. On the other hand, when the temperature detected by the temperature detecting means 29 is higher than a predetermined cut-in temperature, the first circulating fan 28 continues its rotation to circulate within and cool the refrigerator compartment 24, but when the inside temperature of the refrigerator compartment 24 lowers to such an extent that the temperature detected by the temperature detecting means 29 is lower than a predetermined cut-off temperature, the first circulating fan 28 is brought to a halt.
With the first-described prior art refrigerator, a problem has been found that since the cooled air is circulated through the various compartments and chambers, a relatively large number of the air passages are required, resulting in reduction of the maximum available capacity of the refrigerator. Also, the refrigerating system employed therein requires some or all of the air passages to have an increased length from the cooler 6 to the respective compartment or chamber, resulting in reduction in cooling efficiency.
In addition, in the first-described prior art refrigerator, the single cooler 6 is utilized to cool all of the compartments and chambers and is therefore so bulky in size that the adiabatic partition wall 4 is required to be installed at a relatively high level, for example, about 900 mm or more above a support surface such as, for example, a house floor. This makes it difficult to remove or place food materials from or into the crisper chamber 9 that is placed at such a high level above the support surface.
The use of the single cooler 6 to cool all of the compartments and chambers requires the evaporation temperature of the cooler to be designed to a value equal to the lowest available temperature of the freezer compartment 2 and, consequently, the efficiency of the refrigerating system is limited.
Again, considering that the automatic temperature controller 11 is communicated with the freezer compartment 2, the automatic temperature controller 11 is thermally conducted to the crisper chamber 9 within the refrigerator compartment 3 to cool the crisper chamber 9 so excessively that the food materials, particularly vegetables, within the crisper chamber 9 may be frozen undesirably.
On the other hand, the second-described prior art refrigerator shown in FIGS. 10 and 11 is effective to eliminate a possible excessive cooling of the crisper chamber such as occurring in the refrigerator of FIG. 9 and also to eliminate the problems associated with the reduction in capacity and reduction in cooling efficiency of the refrigerating system both resulting from the use of the increased length of the air passage. However, when it comes to installation of the first cooler 27 at a location rearward of the refrigerator compartment 24 and opposite to the front door assembly, a problem would arise that if continued cooling of the freezer compartment 25 is required even though the first circulating fan 28 is brought to a halt as a result of the refrigerator compartment 24 having been cooled sufficiently, a coolant still flows in the first cooler 27 and therefore the refrigerator compartment 24 may be excessively cooled by natural convection. Also, a local area of the crisper box 28 disposed relatively close to the first cooler 27 may be excessively cooled by the first cooler 27 and this is indeed problematic in terms of vegetables kept crisp.
Considering that the second-described prior art refrigerator has a substantial weight and that the crisper box 26 within the refrigerator compartment 24 is held in contact with the bottom thereof, that is defined by an upper surface of the adiabatic partition wall 23, while the first cooler 27 is disposed rearward of the crisper box 26, the crisper box 26 cannot have a sufficient distance between its front and rear walls and would therefore have a relatively small capacity to accommodate the vegetables.
The freezer compartment 25, although less frequently used than the refrigerator compartment 24, is required to have an increased effective capacity. For this reason, if design is made to reduce the depth of the second cooler 30, but to increase the height of the second cooler 30, there is the possibility that the adiabatic partition wall 23 must be reduced in thickness or shifted in position upwardly to accommodate the increased height of the second cooler 30. If the adiabatic partition wall 23 is shifted in position upwardly, the capacity of the refrigerator compartment 24, that is frequently used, would be reduced, posing a problem associated with the proportion of capacity between the freezer compartment 25 and the refrigerator compartment 24. To observe the design proportion in capacity between the refrigerator compartment 24 and the freezer compartment 25 would result in complication of the rear structure of the adiabatic partition wall 23, accompanied by increase in cost of manufacture of the refrigerator along with reduction in production thereof.
Accordingly, the present invention has been devised to eliminate the problems inherent in the prior art bottom-freezer refrigerator and is intended to provide an improved bottom-freezer refrigerator effective to secure sufficiently required capacities with a simplified air passage structure.
Another important object of the present invention is to provide an improved bottom-freezer refrigerator of the type referred to above capable of exhibiting a high cooling efficiency even though the air passage structure is simplified.
A further object of the present invention is to provide an improved bottom-freezer refrigerator of the type referred to above, having no possibility of food materials within the refrigerator compartment and the crisper chamber or box being cooled excessively.
A still further object of the present invention is to provide an improved bottom-freezer refrigerator of the type referred to above, that provides an ease of use and particularly that of a zone of high utility in a household work.
In order to accomplish these objects, the present invention according to one aspect thereof provides a bottom-freezer refrigerator comprises a generally rectangular box-like refrigerator housing including a top division and a bottom division with an adiabatic partition wall intervening between the top and bottom divisions. The top division has a refrigerator chamber and a crisper chamber both defined therein, which crisper chamber is, although not exclusively, dedicated to accommodate food materials required to be kept crisp such as, for example, vegetables. The bottom division has a freezer compartment defined therein.
The bottom-freezer refrigerator of the structure described above also comprises a first cooler provided in the top division at a location spaced from a rear wall portion of the crisper chamber, a first circulating fan disposed in the vicinity of the first cooler, a second cooler provided in the bottom division, and a second circulating fan disposed in the vicinity of the second cooler. The refrigerator chamber and the crisper chamber are cooled by the first cooler in cooperation with the first circulating fan, whereas the freezer compartment is cooled by the second cooler in cooperation with the second circulating fan.
According to the present invention, the capacity of the refrigerator can be secured by utilizing the simplified air passage structure. More specifically, no air passage that extend completely across the adiabatic partition wall is employed to thereby simplify the air passage structure having a reduced length thereof. Shortening of the air passage results in reduction in resistance and, therefore, the top and bottom divisions can be independently cooled by the first and second coolers in cooperation with the first and second circulating fans, respectively, to accomplish a high cooling efficiency. Also, since the first cooler is installed at a location deep rearward of the crisper chamber, neither does thermal conduction to the crisper chamber occur, but the depth of the crisper chamber will not be invaded.
Preferably the crisper chamber is divided into upper and lower rooms so that relatively heavy and/or bulky food materials can be placed in or removed from the crisper chamber which is used highly frequently, at a position convenient to the user. The use of the a low-temperature chamber inside the refrigerator chamber preferably above the crisper chamber and having a capacity smaller than that of the crisper chamber is, if cooled by the first cooler in cooperation with the first circulating fan, effective to substantially eliminate any possible variation in temperature.
Preferably, assuming that the first cooler has a height a, a width b and a depth c and the second cooler has a height A, a width B and a depth C, the first and second coolers have respective sizes that satisfy at least the following relation:
A less than a and C greater than c
This feature makes it possible to use the first cooler of a lean structure sufficient to secure a depth of a zone of high utility and also to use the second cooler of a reduced height to make it possible to expand the zone of high utility.
In addition, in order to render the bottom-freezer refrigerator of the present invention to be more user-friendly and convenient to use, it is preferred that a lower end of the first cooler is positioned a distance of 900 to 1,500 mm above a support surface on which the refrigerator is placed and an upper end of the second cooler is positioned a distance of 400 to 700 mm above the support surface.
In any event, these and other features of the present invention will become clear from the detailed description of preferred embodiments of the present invention which follows with reference to the accompanying drawings.